Method of forming high pressure decorative laminates having registered color and embossing

ABSTRACT

High pressure decorative laminates having registered color and embossing are provided by temporarily laminating a sheet impregnated with an incompletely B-staged melamine resin to an embossed plate and simultaneously embossing such sheet throughout its thickness, by then printing a design on the exposed surface of the now embossed sheet in registry with the embossing thereon, and using this temporary laminate in the production of a high pressure laminate whereby the melamine resin impregnated and color coated sheet is transferred from the embossed plate during lamination.

United States Patent [151 3,661,672

McQuade, Jr. [451 May 9, 1972 [54] METHOD OF FORMING HIGH 3,373,0683/1968 Grosheim et a1 ..l61/D1G. 3 1,936,183 11/1933 Beiger ..l6l/D1G. 3

PRESSURE DECORATIVE LAMINATES HAVING REGISTERED COLOR AND EMBOSSING JohnE. McQuade, Jr., Baltimore, Md.

Assignee: Esso Research and Engineering Company Filed: July 17, 1970Appl. N0.: 62,780

Inventor:

References Cited UNITED STATES PATENTS 10/1970 Ungar et a1. 156/219Primary E.\'aminerRobert F. Burnett Assistant Examiner-James J. BellAIt0rneyKar1 W. Flocks [57] ABSTRACT High 'pressure decorative laminateshaving registered color and embossing are provided by temporarilylaminating a sheet impregnated with an incompletely B-staged melamineresin to an embossed plate and simultaneously embossing such sheetthroughout its thickness, by then printing a design on the exposedsurface of the now embossed sheet in registry with the embossingthereon, and using this temporary laminate in the production of a highpressure laminate whereby the melamine resin impregnated and colorcoated sheet is transferred from the embossed plate during lamination.

8 Claims, 3 Drawing Figures EMBOSSED iPARATER SHEET OR MOULDING PLATE 2oRELEASE SURFACE OR LAYER SUB "F'STAGED OVERLAY 1a RELEASE SHEET [6CUSHION SHEET l4 MOLDING PLATE I2 Patented May 9, 1972 MOULDING PLATE 2ORELEASE SURFACE OR LAYER SUB "a" STAGED OVERLAY |e RELEASE SHEET l6CUSHION s HEET l4 MOLDING PLATE l2 INK OR COLOR OVERPRINT 22 EMBOSSEDOVERLAY I8 CURED T0"B" STAGED EMBOSSED SEPARATOR SHEET OR MOLDING PLATEEMBOSSED SEPARATOR SHEET 2O EMBOSSED OVERLAY I8 OVERPRINT LAYER 22 PRINTSHEET 28 CORE SHEETS 26 MOLDING PLATE 24 [SKA INVENTU/f rm 3 JOHN E.MEQUADE, JR.

AFTORNEY EMBOSSED SEPARATER SHEET OR METHOD OF FORMING HIGH PRESSUREDECORATIVE LAMINATES HAVING REGISTERED COLOR AND EMBOSSING The presentinvention relates to a method of producing a high pressure laminatehaving registered color and embossing and, more particularly, to amethod of making high pressure laminates having aligned color andembossing by a transfer operation.

The production of high pressure laminates is well known and has beencarried out for many years. Generally, the procedures for forming suchlaminates involve providing phenolic (i.e., phenol-formaldehyde) resinimpregnated paper core sheets and melamine (i.e., melamine-formaldehyde)resin decorative and overlay sheets, and pressing the stacked resinimpregnated sheets under heat on the order of 250-310 F. and underpressure of approximately 800-1600 psi until the resin has becomethennoset, thereby providing an extremely hard, attractive and permanentsurfacing material known as a high pressure laminate which has, for manyyears, found use as table tops, desk tops, counter tops, wall paneling,etc.

In the early days of production of high pressure laminates, generallyonly glossy surface laminates were produced by pressing theresin-impregnated sheets between polished die plates under high pressureand temperature, although some attempts were made to provide laminateswith some slight surface irregularities to give satin or texturedfinishes using roughened die plates or through after treatments of thelaminate. In more recent years, it has become increasingly desirableto'provide various types of irregular surfaces, and these range fromsurfaces having relatively shallow depressions, such as matte ortextured surfaces, to relatively deeply sculptured surfaces which have anoticeable threedimensional effect, such as wood grain, leather, slate,etc. With the rising cost of such natural products, it has become evenmore desirable to provide irregularly surfaced high pressure laminateswhich simulate these natural materials.

Thus, high pressure decorative laminates are now manufactured withsmooth surfaces, with textured surfaces or with deeply sculptured orembossed surfaces. In the latter case, a textured surface may besuperimposed on a sculptured or embossed surface. Today, texturedsurfaces are normally obtained by the utilization of a paper-partingsheet or a separating sheet between the laminate components and thesmooth metal plate. These parting sheets, normally used but once andthen thrown away, have small density variations across their surfacewhich, during the laminating procedure, transfer their irregularcross-section to the laminate surface as it flows and cures under heatand pressure. Conventionally, the parting sheet may be Kraft paperbonded to aluminum foil having a thickness of about 0.3 mils, althoughmany other parting sheets are used such as various papers coated and/orimpregnated with various resins and plastic such as fluorocarbon resins,silicon oils or resins, sodium alginate coated papers, etc.

Where it has been desirable to provide a deeply embossed or sculpturedsurface having surface depth variations of as great as 0.007 inch thatduplicate natural products such as slate, leather, wood and the like, ithas generally been necessary to use either extremely expensive machinedor etched steel plates, or, alternatively, thermoset pressing plate diesof the type described in the Jenkins U.S. Pat. No. 2,606,855 or theMichaelson et al. U.S. Pat. Nos. 3,303,081 or 3,311,520. While the useof such dies provides the necessary embossing, many simulated naturalproducts, such as wood grain, must have appropriate color and registrywith the surface embossing or debossing. Unfortunately, the problem ofregistration of color and embossing has proven very difficult,conventional registry techniques being unreliable on a consistent basisin the manufacture of high pressure laminates and also being extremelyexpensive, often involving complex electronic sensing equipment.

A particularly difficult problem presented by the registry of color andembossing in the manufacture of high pressure laminates is the fact thatthe color provided may not overlay the laminate, since any conventionalcolors which might be provided would not be sufficiently resistant toabrasion to meet N.E.M.A. standards, and in such a situation, thelaminate could not properly be called a high pressure laminate."Accordingly, it has heretofore been necessary in providing high pressurelaminates wherein the embossing and color are in registry, to separatelyprovide the printing and the embossing and to then, prior to thelamination, align or register the separately produced items, and tomaintain the registration during the laminating operation. Even wherethis has been successfully accomplished, the cost has been high, notonly because of the complexity of the procedure, but also because of thehigh percentage of imperfect laminates produced thereby which must bediscarded or sold as seconds.

It is, accordingly, an object of the present invention to overcome thedefects of the prior art, such as indicated above. It is another objectof the present invention to produce decorative high pressure laminates,having registered color and embossing, in a simplified and inexpensivemanner.

It is another object of the present invention to provide a new andimproved method for inexpensively manufacturing high pressure laminateshaving registered color and embossing.

It is another object of the present invention to provide a transferprocedure for producing relatively low cost, high pressure decorativelaminates having registered embossing and color.

In the present exemplification of this invention, there is disclosed amethod by which an embossed temporary or transfer laminate is producedwhich is then provided with color in association with the embossedportions, and wherein the embossed and colored temporary laminate isthen used in a high pressure laminating procedure wherein the previouslyembossed and colored element is transferred from its temporary supportto form the upper surface of the high pressure laminate havingregistered embossing and color.

To the attainment of these ends and the accomplishment of the above aswell as other new and useful objects as will appear below, the inventionrelates to the features of novelty in substantially the construction,combination and arrangement of the several parts hereinafter more fullydescribed and shown in the accompanying drawing as an exampleillustrating this invention, and in which:

FIG. 1 schematically shows the formation of a transfer laminate in thepresent invention;

FIG. 2 schematically shows a temporary transfer laminate produced asshown in FIG. 1 having color applied thereto; and

FIG. 3 shows utilization of the colored transfer laminate of FIG. 2 inthe production of a high pressure laminate having registered color andembossing.

Briefly, the process of producing a decorative laminate, having alignedor registered embossing and color on its decorative side, employs atemporary transfer laminate of an overlay on a separator sheet whichtransfers embossing, overlay and color to the high pressure laminateduring its production. Accordingly, in FIG. 1 there is shownschematically an operation for forming a temporary transfer laminate 10.Upon a molding plate 12 there is'assembled in a stack from the bottomup, a cushion sheet 14, a release sheet 16, a melamine resin impregnatedoverlay sheet 18 wherein the melamine resin is cured to a state lessthan the B-stage, and an embossed separator sheet or embossed moldingplate 20.

While a molding plate of the type described in the Jenkins U.S. Pat. No.2,606,855 or the Michaelson et al. U.S. Pat. Nos.

3,303,081 or 3,311,520 may be used, or even an expensive transferlaminate of FIG. 2, while the other die member may be the molding plate20, when a thick molding plate is used such as the type shown in theMichaelson et al. patents; however, if a thin embossed separator sheetof the type described in the Scher and Ungar application, Ser. No.865,894, is used, then a second molding plate similar to molding plate12 will of necessity be used above the embossed separator sheet toprovide the other die member.

The cushion sheet 14 maybe any suitable element, or a plurality thereof,for interposition between the lower molding plate 12 and the overlayelement 18, the purpose of the cushion sheet 14 being to prevent themolding plate 12 from unduly flattening the overlay 18 during thelaminating operation in the production of the temporary transferlaminate 10 of FIG. 2. It has been found that a simple sheet of Kraftpaper, or other paper, is suitable as a cushion sheet 14 and, hence,because of its low cost, such a Kraft paper sheet is the preferredcushion sheet 14. However, any fibrous mat, or even a thin rubber sheet,could suitably serve as the cushion sheet 14.

It is necessary, in accordance with the present invention, to preventadhesion of the cushion sheet 14 to the overlay 18 during the productionof temporary transfer laminate 10. This may be accomplished by eitherproviding a suitable non-adherent coating to the upper surface of thecushion sheet 14, by providing a cushion 'sheet of such structure thatit is inherently non-adherent, or, preferably, by interposing aconventional release sheet 16 between the cushion sheet 14 and theoverlay 18. Commercially available release sheets, also known asseparator or parting sheets or membranes, include aluminum foil,silicone resin treated paper, silicone oil treated paper, Quillontreated paper, fluorocarbon resin treated paper, sodium alginate treatedpaper, etc., and any of these may be used as the release sheet 16, solong as the non-adherent surface of the release sheet 16 or the cushionsheet 14 is facing the overlay 18.

One of the critical features of the present invention resides in thenature of the overlay 18 which is assembled in the stack illustrated inFIG. 1. As indicated above, this overlay 18 is impregnated with melamineresin or other suitable resins compatible with the resin system of theultimate laminate produced, and having the necessary properties, whichresin is cured to a stage which is less than the normal B-stage. Thepaper constituting the overlay 18 is preferably a-cellulose paper sincethis material, as is well known, is transparent when impregnated withmelamine resin and cured to the normal extent during formation of thehigh pressure laminate. However, whereas during normal laminatingprocedures the overlay sheet is impregnated with the melamine resinadvanced to the B-stage of cure, in the present invention it isessential that the overlay be green" or cured to a stage less than theB-stage.

The incompletely B-staged a-cellulose overlay sheet is essentially anoverlay sheet which has been impregnated with a water dispersion ofmelamine-formaldehyde resin as is conventional and wherein the volatileshave been dried at a relatively low temperature to reduce or inhibit thedegree of cure which normally accompanies the drying of the overlaypaper.

Generally, the a-cellulose paper will contain, per 100 pounds of suchpaper, about -70 pounds of solid melamine resin and about 10-15 poundsof volatile solvents, and the resin will have a flow* percent Flowpercent is determined by weighing an impregnated sample, pressing thesample at 1,000

psi and 300 F. between sheets of aluminum foil to squeeze out flowableresin, reweighing the sample without that portion of the resin which hasbeen squeezed out, and dividing the loss in weight of the sample by theoriginal sample weight and multiplying by 100.) of about 20-35.

After formation of the assembly stack of FIG. 1, such stack is pressedunder heat and pressure to emboss the overlay 18 throughout itsthickness, thereby providing elevated and depressed portions, to advancethe cure of the melamine impregnant to the B-stage and to laminate theoverlay sheet 18 to the embossed plate or separator sheet 20. Thepressing under heat and pressure need not be accomplished underconditions as severe as those normally used in the production of highpressure laminates; thus, the pressing may be carried out at about400-600 psi and at about 200 F. for about 5-15 minutes. Highertemperatures may be used in which case the time will be shorter, orlower temperatures may be used in which case'a greater time period willbe necessary. One satisfactory time-temperature profile comprisesheating up to 222 F. during the first 5 minutes, pressing at 222 F. forthe next 3 minutes, cooling to F. for the next 4 minutes, cooling from150-l00 F. for the next 4 minutes, and finally then provided withelevated portions 182 and with depressedportions 184 on its exposedsurface.

The next step in the operation comprises merely applying a suitablecolor or ink design 22 on the exposed surface of the embossed overlay 18as shown in FIG. 2. The ink or color may be printed on the overlay 18 soas to fill the depressions 184 or it may be printed only on the elevatedportions182 as is illustrated in FIG. 2. At any rate, it will be evidentthat the coloring or ink is applied in a very simple manner directlyonto the overlay coated embossed separator sheet or transfer laminate 10in exact registration with the embossed pattern, for example by aninking roller. The printing may be accomplished by any other knownmanner, e.g., the silk screen method, valley printing, gravure, etc.Conventional inks and color, normally used to give color to print sheetsused in the formation of high pressure laminates, may be used to providethe overprint color layer 22. After application of the ink or coloroverprint 22 and drying thereof, the temporary transfer laminate 10 willhave the appearance shown in FIG. 2.

As can best be seen in FIG. 2, the temporary transfer laminate 10comprises a temporary support 20 having a variable thickness, a smoothbacking and an embossed front, and the support 20 is provided with arelease surface on its embossed front. Above the support 20 is anembossed, melamine resin impregnated porous sheet 18, temporarilylaminated to the release surface of the support 20, the sheet 18 beingof generally uniform thickness, but conforming to the embossed surfacecharacteristics of the support 20. A color coating 22 is provided on theexposed surface of the resin impregnated sheet 18, the color coatingbeing discontinuous and conforming to the embossing. The color coating22 is compatible with the melamine resin impregnant.

The temporary transfer laminate 10 is then ready for use in a highpressure laminating procedure to produce the high pressure laminatehaving registered color and embossing. This is accomplished by providingan assembly as shown in FIG. 3 comprising, from the bottom up, a moldingplate 24, a plurality of phenolic or other suitable resin impregnatedcore sheet 26, a conventional colored print sheet 28 and the temporarytransfer laminate 10. As indicated above, the core sheets and the printsheet are of conventional construction being, preferably, phenolic resinimpregnated paper sheets and a colored melamine resin impregnateda-cellulose sheet, respectively.

The assembly in FIG. 3 is then pressed under normal conditions of highheat and pressure to form a high pressure laminate. As indicated above,these conditions are normally on the order of 800-1 ,600 psi and on theorder of 250-3 10 F.

After the assembly has been cured and the high pressure laminate formed,the embossed separator sheet 20 is then stripped from the upper surfaceof the resultant high pressure laminate, the embossed overlay 18 havingbeen laminated to the print sheet 28 with the color layer 22 trappedtherebetween. It will be seen that portions of the resultant laminatewill be provided with color from the o erprint layer 22 which is nowprotected by the embossed overlay 18 while other portions will beprovided with color provided by the print sheet 28, also protected bythe overlay 18. It will also be seen that there is exact registrybetween the embossing and the different colors.

The importance of using a sub-B-staged overlay 18 during the firstlaminating procedure to produce the temporary transfer laminate of FIG.2 will now be more readily understood. Thus, if a normally B-stagedmelamine resin impregnated overlay is used in the first laminatingprocedure, the cure during such first lamination will proceed so farthat during the second laminating procedure, during which the transfer10 is used, the cure will be advanced even further and so the ultimateproduct will be unsatisfactory because the embossed overlay will havebeen overcured. In other words, the advantage of the green overlay isthat it can tolerate what amounts to double press exposure and stilldevelop normal adhesion to the print sheet 28 during the secondlaminating operation.

Some advantages of the present invention are that the transfer laminate10 is handled as a single unit capable of simultaneously embossing andcoloring a high pressure laminate with registry. No chance exists forthe embossing medium and the color medium to shift out of registryduring production, handling and processing, thereby giving a new resultwhich has not been possible with past attempts to manufacture registeredembossed high pressure laminates. Further more, the color is maintainedunder the overlay where it is completely protected from wear andabrasion, the registered embossed laminate meeting N.E.M.A. heatresistance and blistering standards since by starting with sub-B-stagedoverlay, sufficient resin flow is retained so that normal adhesion ofthe overlay to the print sheet is developed in the final laminatepressing cycle.

The possibilities for producing registered three-dimensional laminatesby the present method are many and varied, limited only by imagination.Decorative patterns of intricate design or simple shapes registered withone or more colors with different textures may be produced in relief orin intaglio. Wood grain patterns may be embellished withthree-dimensional ticking to give the feel and appearance of naturalwood.-

Laminates may be produced displaying messages where the characters areraised (embossed) or lowered (debossed) and of different colors andtextures surrounding such characters. Additionally, while theexemplified embodiment shows the production of a one-side-good laminate,it will be understood that two-side-good laminates can also be made bythe present operation.

To more fully describe the invention, specific examples, offered forillustration but not limitation, are provided:

EXAMPLE I Step 1: Production of Sub-B-Staged Overlay Sheet 18 (GreenOverlay) Conventional a-cellulose impregnating paper having a basisweight of 29-31 pounds is saturated with melamine-formaldehyde resinsolution in a conventional manner. The resin comprises 45-55 percentsolids and contains 0.1-1.0 percent chloroacetamide as a latentcatalyst. This latent catalyst has an activating temperature ofapproximately 240 F. After impregnating the a-cellulose paper, the paperis passed to a three-zoned convection oven where it is dried of resinsolution volatiles. The oven is operated at temperatures significantlybelow the catalyst activation temperature but sufficient to reduce theresin solution volatiles so the impregnated paper is dry to the touchafter passage through the oven. In the present situation in productionof the green overlay, the oven length was 67 feet, the paper speed was52 feet per minute, and the time of the paper in the oven was 1.29minutes. The oven temperature conditions were as follows:

Zone 1 170 F. Zone 2 190 F. Zone 3 200 F.

The green overlay, after removal from the oven, had a resin pickup of64-69 percent, a volatility of 12-15 percent and a flow of 20-35percent. Step 2: Formation of Temporary Transfer Laminate 10 Theassembly of FIG. 1, using a separator sheet 20 of the Scher and Ungartype of Ser. No. 865,894, was pressed in a heated platen press at aplaten temperature of 225 F. at 500 psi under the followingtime-temperature profile:

Time (Minutes) Temperature (Degrees F.)

0-5 222 5-8 222 8-12 222-150 (cooling begun at 8 min.) 12-18 ISO- Thepress was opened after 18 minutes and the overlay faced separator 10(but without the color overprint 22) was removed. This procedureprovides the overlay temporarily adhered to and formed to the exactshape of the embossed separator sheet 20. The resin contained in theoverlay at this point is at or very near the normal B-stage as measuredby flow determination (7-14 percent).

Step 3: Printing Overlay Faced Embossed Separator 10 The embossedoverlay faced separator 10 is placed with its overlay side up, and asilk screen capable of printing the exact pattern of the embossingsuperimposed over the embossing in exact registry therewith is placedthereover. The pattern 22 is printed onto the embossed overlay coatedseparator using a conventional laminating ink normally used in theprinting of print sheets such as print sheet 28. The resultant coloredtemporary transfer laminate 10 is shown in FIG. 2.

Step 4: Utilization of the Temporary Laminate 10 to Produce RegisteredThree-Dimensional Laminate An assembly such as shown in FIG. 3 isprovided using the temporary laminate 10, a conventional melamineresin-impregnated a-cellulose print sheet 28 and conventional phenolicimpregnated core sheets 26. The composite is pressed in a normal mannerwith typical molding cycle being 1,000 psi, 300 F. for 30 minutes, withcooling under pressure and utilizing a total cycle time of about 60minutes. The separator 20 embosses the laminate with the printed overlaysheet 18 releasing therefrom during this final curing step and becomingthe top ply of the completed laminate. The resultant laminate fullymeets N.E.M.A. standards, and yet there is perfect registration of colorand embossing.

EXAMPLE 2 The same operation as described above in Example 1 wasrepeated except that the ink overprint 22 was applied to the temporarytransfer laminate 10 by merely using an ink rubber roller. As with thepreceding example, the results were excellent with no variation in theregistry of the texture and the coloring.

The foregoing description of a specific embodiment will so fully revealthe general nature of the invention that others can, by applying currentknowledge, readily modify such specific embodiment and/or adapt it forvarious applications without departing from the generic concept, and,therefore, such adaptations and modifications should and are intended tobe comprehended within the meaning and range of equivalents of thedisclosed embodiment. It is to be understood that the phraseology orterminology employed herein is for the purpose of description and not oflimitation.

What is claimed is:

2. an overlay sheet impregnated with an incompletely B- staged melamineresin, and 3. a non-adherent cushion sheet; pressing said stack underheat and pressure to emboss said overlay sheet throughout its thicknessso as to provide elevated and depressed portions on its exposed surface,to advance the cure of the melamine impregnant to the B-stage and tolaminate said overlay sheet to said embossed plate; c. printing a designon the exposed surface of said overlay sheet; providing an assemblyof 1. said embossed plate having said printed overlay thereon, 2. aresin impregnated print layer facing said printed overlay, and 3.a'plurality of resin impregnated core layers; e. pressing said assemblyunder high heat and pressure to form a high pressure laminate; andstripping said embossed plate from the upper surface of said highpressure laminate whereby portions thereof are provided with the colorprinted on said overlay sheet in step (c), the remainder being providedwith the print of said print layer.

2. A method in accordance with claim 1, wherein said printing in step(c) provides a color coating over said exposed elevated portions of saidoverlay sheet, to thereby produce in said high pressure laminatedebossed portions provided vwith said color printed on said elevatedportions of said overlay sheet in step (c), the remainder of saidlaminate being provided with the print of said print layer.

3. A method in accordance with claim 1 comprising preliminary to step(a),

impregnating a-cellulose paper with a melamine resin solution of nomore'than about 55 percent by weight solids, and drying said paper toproduce said overlay sheet impregnated with incompletely B-stagedmelamine resin.

4. A method in accordance with claim 1 wherein said ,8- staged melamineresin impregnated overlay sheet comprises a-cellulose paper containing,per pounds of a-cell ulose paper, about 60-70 pounds of solid melamineresin and about 10-15 pounds of volatile solvents, said impregnatedoverlay sheet having a flow percent of about 20-35.

5. A method in' accordance with claim 1 wherein said pressing in step(b) iscarried out at about 400-600 psi andat a temperature on the order.of about 200 F.

6. A method in accordance with claim 1 wherein said embossed platecomprises an embossed impregnated separator sheet having a non-stickfacing.

7. A method in accordance with claim 1 wherein said nonadherent cushionsheet in step (a) comprises a paper sheet and further comprising arelease sheet or parting membrane :thereon.

8. A method in accordance with claim 1 wherein in said assembly of stepd) said resin impregnated print layer comprises a-cellulose paperimpregnated with melamine resin at the B-stage, and said resinimpregnated core layers each-cornprise paper impregnated with phenolicresinat the B-stage.

2. an overlay sheet impregnated with an incompletely B-staged melamineresin, and
 2. a resin impregnated print layer facing said printedoverlay, and
 2. A method in accordance with claim 1, wherein saidprinting in step (c) provides a color coating over said exposed elevatedportions of said overlay sheet, to thereby produce in said high pressurelaminate debossed portions provided with said color printed on saidelevated portions of said overlay sheet in step (c), the remainder ofsaid laminate being provided with the print of said print layer.
 3. AmeThod in accordance with claim 1 comprising, preliminary to step (a),impregnating Alpha -cellulose paper with a melamine resin solution of nomore than about 55 percent by weight solids, and drying said paper toproduce said overlay sheet impregnated with incompletely B-stagedmelamine resin.
 3. a plurality of resin impregnated core layers; e.pressing said assembly under high heat and pressure to form a highpressure laminate; and f. stripping said embossed plate from the uppersurface of said high pressure laminate whereby portions thereof areprovided with the color printed on said overlay sheet in step (c), theremainder being provided with the print of said print layer.
 3. anon-adherent cushion sheet; b. pressing said stack under heat andpressure to emboss said overlay sheet throughout its thickness so as toprovide elevated and depressed portions on its exposed surface, toadvance the cure of the melamine impregnant to the B-stage and tolaminate said overlay sheet to said embossed plate; c. printing a designon the exposed surface of said overlay sheet; d. providing an assemblyof
 4. A method in accordance with claim 1 wherein said B-staged melamineresin impregnated overlay sheet comprises Alpha -cellulose papercontaining, per 100 pounds of Alpha -cellulose paper, about 60-70 poundsof solid melamine resin and about 10-15 pounds of volatile solvents,said impregnated overlay sheet having a flow percent of about 20-35. 5.A method in accordance with claim 1 wherein said pressing in step (b) iscarried out at about 400-600 psi and at a temperature on the order ofabout 200* F.
 6. A method in accordance with claim 1 wherein saidembossed plate comprises an embossed impregnated separator sheet havinga non-stick facing.
 7. A method in accordance with claim 1 wherein saidnon-adherent cushion sheet in step (a) comprises a paper sheet andfurther comprising a release sheet or parting membrane thereon.
 8. Amethod in accordance with claim 1 wherein in said assembly of step (d)said resin impregnated print layer comprises Alpha -cellulose paperimpregnated with melamine resin at the B-stage, and said resinimpregnated core layers each comprise paper impregnated with phenolicresin at the B-stage.